package day07;

import java.util.Random;

public class VerificationCode {
    public static void main(String[] args) {
        String code=generateVerCode(40);
        System.out.println("验证码："+code);

    }
    public static String generateVerCode(int len){
       String code="";
       char[] chs={'a','b','c','d','e','f','g','h','i','j','k','l','m',
                   'n','o','p','q','r','s','t','u','v','w','x','y','z',
                   'A','B','C','D','E','F','G','H','I','J','K','L','M',
                   'N','O','P','Q','R','S','T','U','V','W','X','Y','Z',
                   '0','1','2','3','4','5','6','7','8','9'};
        Random rand=new Random();
       for (int i=1;i<=len;i++){
           //int index=(int)(Math.random()* chs.length);

           int index= rand.nextInt(chs.length);
           code +=chs[index];
       }
       return code;
    }
}
